Detecting fractures in artificial heart valves

In recent years, it has been established that the minor outlet closure strut in certain artificial heart valves may suffer from mechanical defects. These defects appear as cracks or fractures near the junction of a leg of this strut with the main ring of the device. As a consequence, the valve occluder may escape from the device, which subjects the patient to a lethal risk. In view of this development, one of the authors approached several research groups with the question whether, from their expertise, it would be possible to develop techniques for assessing the quality of existing heart valves implanted in patients. The present paper presents the first steps towards using pulsed electromagnetic waves for this purpose. The principal difficulty with generating electromagnetic effects in a biological environment is that blood and live tissue are highly dispersive, and, therefore, extremely lossy. This means that any measurement will definitely have to be invasive, e.g., via a catheter. Even in such circumstances, it seems doubtful whether a significant electromagnetic effect can be generated and measured. To investigate this, it was decided to first model a simplified but representative configuration with the aid of computational techniques.